In recent years, a sound system that can obtain a high sense of reality by reproducing the audio signal of audio recorded in multi-channels using speakers which are disposed so as to surround the periphery of a user is generally used. Further, a service that distributes the audio of a 5.1-ch system or a 7.1-ch system via recording media, networks, or the like such as broadcast or optical disks is performed. In the sound system including five or seven speakers disposed so as to surround the periphery of the user, the audio signal provided by these systems is also output (reproduced) from the back of the user. Further, a 22.2-ch system that can output audio by a plurality of speakers installed at the upper and the lower of the space where a user exists is also proposed.
In a case where the audio of these systems is reproduced, when a plurality of speakers are disposed as a recommended disposition, an excellent sound effect can be produced and a high sense of reality is reproduced. However, in the 5.1-ch system and the 7.1-ch system, it is recommended that five or seven speakers are disposed at the positions of an equal distance from the user on the plane of the height of the user's ear. Further, in the 22.2-ch system, it is recommended that 22 speakers are disposed at the positions of an equal distance from the user in three-stage heights. As described above, in ordinary homes, it is difficult to achieve the sound system in which a plurality of speakers are disposed, and thus a method that disposes the speakers at the required positions only when needed and puts away the speakers when not in use, is performed.
In order to solve the problems, for example, in PTL 1, a technique that ensures the same effect as the case where the speakers are disposed at the recommended positions by performing adjustment of delay or like that is related to the audio output of the speaker which is installed at a distance from the recommended disposition position, is disclosed.
This technique is a technique that sequentially outputs a test signal from the speakers, receives the test signal by the microphone installed at the position of the user, and changes the delay time, the level, and the like of the audio signal supplied to each speaker based on the result. This technique allows the user to enjoy surround sounds even when using the speaker which is installed at a distance from the recommended disposition position.